AFAIK his paintings were never intended to be 'realistic' in the sense we may value, but instead: symbolic. He played with color, intensity, and perspective, expressing vast emotion, and in some cases, turmoil. His mental health and state changed throughout his life which you can almost "see" evolving through his art as he aged. He's incredible to read about - https://www.vangoghmuseum.nl/en/art-and-stories/stories/vinc...

EDIT: I find this really interesting: a visual timeline of how his relationship with alcohol changed his artistic style in various phases of his life: https://www.frontiersin.org/files/Articles/536428/fpsyt-11-0...